Mine is 3.4" and I run 9lbs. We thought about going to a 2.8", but decided not to run the boost
that high on pump gas. (And no, I do not know what that would have produced.)
BTW, the size of your pulley is stamped on the front of it. I mention that because
someone on this forum did not know it and was trying to measure it
. Their name will stay with me.
